Abstract. Analysis of data from the ${}^{22}\mathrm{Ne}$(${}^3\mathrm{He},p$) ${}^{24}\mathrm{Na}$ reaction has been extended to include 18 angular distributions for states between 4.7 and 5.9 MeV. A distorted-wave Born-approximation analysis allows the determination of ℓ value(s) for most of them. Results for $J^{\pi }$ are compared with previous information. In general, agreement is good. Some apparent disagreements between current and past results are indicative of population of a different state in this reaction than the nearby one listed in the compilation.

In the paper the nonlinear generalization of the time blocking approximation (TBA) is presented. The TBA is one of the versions of the extended random-phase approximation (RPA) developed within the Green-function method and the particle-phonon coupling model. In the generalized version of the TBA the self-consistency principle is extended onto the phonon space of the model. The numerical examples show that this nonlinear version of the TBA leads to the convergence of results with respect to enlarging the phonon space of the model.

Parity doublet structures are established in ${}^{216}\mathrm{Fr}$, which lies at the lower boundary of enhanced octupole collectivity in the trans-lead region. The newly identified levels are established as the simplex partner of a previously reported band leading to parity doublets with small ($\sim 55$ keV) average energy splitting, a feature typical of nuclei with near-static octupole deformation. The observed levels do not follow a regular pattern of rotational bands, indicating low quadrupole collectivity. However, enhanced octupole correlations are evident from the small energy splitting and large B(E1)/B(E2) values. Staggering in E1 transition energies and B(E1)/B(E2) ratios is noted. The enhancement of octupole correlations in ${}^{216}\mathrm{Fr}$ is attributed to the availability of a neutron orbital with a K = 3/2 component.

To describe quantal collective phenomena, it is useful to requantize the time-dependent mean-field dynamics. We study the time-dependent Hartree-Fock-Bogoliubov (TDHFB) theory for the two-level pairing Hamiltonian, and compare results of different quantization methods. The one constructing microscopic wave functions, using the TDHFB trajectories fulfilling the Einstein-Brillouin-Keller quantization condition, turns out to be the most accurate. The method is based on the stationary-phase approximation to the path integral. We also examine the performance of the collective model which assumes that the pairing gap parameter is the collective coordinate. The applicability of the collective model is limited for the nuclear pairing with a small number of single-particle levels, because the pairing gap parameter represents only a half of the pairing collective space.

In conjunction with models, the experimental observable of total multiplicity can be used to check if the data contain the signature of phase transition and if it is first order. Two of the models reach similar conclusions. The third one is quite different.

A statistical multifragmentation model (SMM) is applied to the experimentally observed multifragmentation events in an intermediate heavy-ion reaction. Using the temperature and symmetry energy extracted from the isobaric yield ratio (IYR) method based on the modified Fisher model (MFM), SMM is applied to the reaction ${}^{64}\mathrm{Zn}+{}^{112}\mathrm{Sn}$ at 40 MeV/nucleon. The experimental isotope distribution and mass distribution of the primary reconstructed fragments are compared without afterburner and they are well reproduced. The extracted temperature $T$ and symmetry energy coefficient $a_{\mathrm{sym}}$ from SMM simulated events, using the IYR method, are also consistent with those from the experiment. These results strongly suggest that in the multifragmentation process there is a freezeout volume, in which the thermal and chemical equilibrium is established before or at the time of the intermediate-mass fragments emission.

Longitudinal momentum ($P_{\mathrm{L}}$) distributions of projectilelike fragments produced at $E=290\mathrm{MeV}/\mathrm{nucleon}$ are investigated. $P_{\mathrm{L}}$ distributions of fragments produced by Ar and Kr beams with a wide variety of targets (C, Al, Nb, Tb, and Au) were measured using the fragment separator at HIMAC. $P_{\mathrm{L}}$ distributions observed for fragments with a wide range of mass losses $\mathrm{\Delta }A$ (1–30 for Ar beam and 1–64 for Kr beam), show a slightly, but definitely asymmetric nature. The peak shift and width were obtained from the observed $P_{\mathrm{L}}$ distributions. No significant target dependence was found in either the peak shift or width. For the practical application, the variation in momentum peak shift with fragment mass ($A_{\mathrm{F}}$) was represented by a parabolic function. The width on the high-$P_{\mathrm{L}}$ side (${\sigma }_{\mathrm{High}}$) is well reproduced by the Goldhaber formula, which is obtained from the contribution of the Fermi momentum. The behavior of the reduced width, ${\sigma }_0$, obtained from ${\sigma }_{\mathrm{High}}$ via the Goldhaber formulation, is consistent with the mass-dependent Fermi momentum of a nucleon. The width on the low-$P_{\mathrm{L}}$ side (${\sigma }_{\mathrm{Low}}$) is markedly larger than ${\sigma }_{\mathrm{High}}$ and exhibits a clear $A_{\mathrm{F}}$ dependence.

In high energy heavy ion collisions and interacting cold atom systems, large elliptic flow anisotropies have been observed. For the large opacity ($\rho \sigma L\sim {10}^3$) of the latter hydrodynamics is a natural consequence, but for the small opacity ($\rho \sigma L\sim 1$) of the former the hydrodynamic description is questionable. To shed light onto the situation, we simulate the expansion of a low density argon ion (or atom) system, initially trapped in an elliptical region, under the Coulomb interaction (or elastic scattering). Significant elliptic anisotropy is found in both cases, and the anisotropy depends on the initial spatial eccentricity and the density of the system. The results may provide insights into the physics of anisotropic flow in high energy heavy ion collisions and its role in the study of quantum chromodynamics.

Using the conservation laws for charge, energy, momentum, and angular momentum, we derive hydrodynamic equations for the charge density, local temperature, and fluid velocity, as well as for the polarization tensor, starting from local equilibrium distribution functions for particles and antiparticles with spin $1/2$. The resulting set of differential equations extends the standard picture of perfect-fluid hydrodynamics with a conserved entropy current in a minimal way. This framework can be used in space-time analyses of the evolution of spin and polarization in various physical systems including high-energy nuclear collisions. We demonstrate that a stationary vortex, which exhibits vorticity-spin alignment, corresponds to a special solution of the spin-hydrodynamical equations.

Excited states in ${}^{155}\mathrm{Tm}$ have been populated via the reaction ${}^{144}\mathrm{Sm}$(${}^{16}\mathrm{O}, p4n$)${}^{155}\mathrm{Tm}$ at a beam energy of 118 MeV. The ground-state band has been extended and a new side band of the ground-state band is identified. E-GOS curves and potential energy surface calculations are employed to discuss the structure evolution of the ground-state band. The newly observed side band in ${}^{155}\mathrm{Tm}$ is discussed based on the spin/energy systematics. In particular, the phenomenon of seniority inversion is proposed in ${}^{155}\mathrm{Tm}$, and a systematic study of this phenomenon in the $A\approx 150$ mass region is performed.

Ten years ago, highly excited states were found in ${}^9\mathrm{Li}$ and ${}^{10}\mathrm{Be}$ a few hundred kilovolts above the proton decay threshold. These physical states are too low in energy to be the isospin-stretched configuration of the decay channel (the isobaric analog or $T_{>}$). However, these states can be understood by a continuum cognizant shell model as strongly mixed states of lower isospin ($T_{<}$), where the mixing is largely mediated by the open neutron channels but ushered in energy to be just above the proton threshold.

Starting from general expressions of well-chosen symmetric nuclear matter quantities derived for both zero- and finite-range effective theories, we derive some universal relations between them. We first show that, independently of the range, the two-body contribution is enough to describe correctly the saturation mechanism but gives an effective mass value around $m^{*}/m\simeq 0.4$ when the other properties of the saturation point are set near their generally accepted values. Then, we show that a more elaborated interaction (for instance, an effective two-body density-dependent term on top of the pure two-body term) is needed to reach the accepted value $m^{*}/m\simeq 0.7–0.8$.

Statistical analysis of distributions of the collective states in actinide and rare-earth nuclei is performed in terms of the nearest-neighbor spacing distribution (NNSD). Several approximations, such as the linear approach to the level repulsion density and that suggested by Brody to the NNSDs were applied for the analysis. We found an intermediate character of the experimental spectra between the order and the chaos for a number of rare-earth and actinide nuclei. The spectra are closer to the Wigner distribution for energies limited by 3 MeV, and to the Poisson distribution for data including higher excitation energies and higher spins. The latter result is in agreement with the theoretical calculations. These features are confirmed by the cumulative distributions, where the Wigner contribution dominates at smaller spacings while the Poisson one is more important at larger spacings, and our linear approach improves the comparison with experimental data at all desired spacings.

The overall transverse momentum balance and the redistribution of the lost energy from hard jets for asymmetric dijet events in PbPb collisions at $2.76A$ TeV at the LHC is studied within a multiphase transport (AMPT) model. A detailed analysis is performed for the projected transverse momentum $\langle {p/}_T^{\left|\right|}\rangle$ contributed from the final charged hadrons carrying different transverse momenta and emitted from different angular directions. We find that the transverse momentum projection $\langle {p/}_T^{\left|\right|}\rangle$ in the leading jet direction is mainly contributed by hard hadrons ($p_T>8.0\mathrm{GeV}/c$) in both peripheral and central PbPb collisions, while the opposite direction in central collisions is dominated by soft hadrons ($p_T=0.5–2.0\mathrm{GeV}/c$). The study of in-cone and out-of-cone contributions to $\langle {p/}_T^{\left|\right|}\rangle$ shows that these soft hadrons are mostly emitted at large angles away from the dijet axis. Our AMPT calculation is in qualitative agreement with the CMS measurements and the primary mechanism for the energy transported to large angles in the AMPT model is the elastic scattering at the partonic stage. Future studies including also inelastic processes should be helpful in understanding the overestimation of the magnitudes of in-cone and out-of-cone imbalances from our AMPT calculations, and shed light on different roles played by radiative and collisional processes in the redistribution of the lost energy from hard jets.

We present a comprehensive and pedagogic discussion of the properties of photons in cold and dense nuclear matter based on the resummed one-loop photon self-energy. Correlations among electrons, muons, protons, and neutrons in $\beta$ equilibrium that arise as a result of electromagnetic and strong interactions are consistently taken into account within the random phase approximation. Screening effects, damping, and collective excitations are systematically studied in a fully relativistic setup. Our study is relevant to the linear response theory of dense nuclear matter, calculations of transport properties of cold dense matter, and investigations of the production and propagation of hypothetical vector bosons such as the dark photons.

In heavy-ion collisions, after the quark-gluon plasma there is a hadronic gas phase. Using effective Lagrangians, we study the interactions of charmed mesons which lead to $J/\psi$ production and absorption in this gas. We update and extend previous calculations introducing strange meson interactions and also including the interactions mediated by the recently measured exotic charmonium resonances $Z\left(3900\right)$ and $Z\left(4025\right)$. These resonances open new reaction channels for the $J/\psi$, which could potentially lead to changes in its multiplicity. We compute the $J/\psi$ production cross section in processes such as $D_{\left(s\right)}^{(*)}+{\overline{D}}^{(*)}\to J/\psi +(\pi ,\rho ,K,K^{*})$ and also the $J/\psi$ absorption cross section in the corresponding inverse processes. Using the obtained cross sections as input to solve the appropriate rate equation, we conclude that the interactions in the hadron gas phase lead to a 20–24% reduction of the $J/\psi$ abundance. Within the uncertainties of the calculation, this reduction is the same at the Relativistic Heavy Ion Collider and the large Hadron Collider.

We show that fully aligned neutron-proton pairs play a crucial role in the low-energy spectroscopy of nuclei with valence nucleons in a high-$j$ orbital. Their dominance is valid in nuclei with valence neutrons and protons in different high-$j$ orbitals as well as in $N=Z$ nuclei, where all nucleons occupy the same orbital. We demonstrate analytically this generic feature of the neutron-proton interaction for a variety of systems with four valence nucleons interacting through realistic, effective forces. The dominance of fully aligned neutron-proton pairs results from the combined effect of (i) angular momentum coupling and (ii) basic properties of the neutron-proton interaction.

The $\alpha$-decay half-lives of the recently synthesized superheavy nuclei (SHN) are investigated by employing the density dependent cluster model. A realistic nucleon-nucleon ($\mathit{NN}$) interaction with a finite-range exchange part is used to calculate the microscopic $\alpha$-nucleus potential in the well-established double-folding model. The calculated potential is then implemented to find both the assault frequency and the penetration probability of the $\alpha$ particle by means of the Wentzel-Kramers-Brillouin (WKB) approximation in combination with the Bohr-Sommerfeld quantization condition. The calculated values of $\alpha$-decay half-lives of the recently synthesized Og isotopes and its decay products are in good agreement with the experimental data. Moreover, the calculated values of $\alpha$-decay half-lives have been compared with those values evaluated using other theoretical models, and it was found that our theoretical values match well with their counterparts. The competition between $\alpha$ decay and spontaneous fission is investigated and predictions for possible decay modes for the unknown nuclei ${}_{118}{}^{290-298}\mathrm{Og}$ are presented. We studied the behavior of the $\alpha$-decay half-lives of Og isotopes and their decay products as a function of the mass number of the parent nuclei. We found that the behavior of the curves is governed by proton and neutron magic numbers found from previous studies. The proton numbers $Z=114$, 116, 108, 106 and the neutron numbers $N=172$, 164, 162, 158 show some magic character. We hope that the theoretical prediction of $\alpha$-decay chains provides a new perspective to experimentalists.

A shell-model method for calculating Gamow-Teller (GT) transition rates in heavy deformed odd-mass nuclei is presented. The method is developed within the framework of the projected shell model. To implement the computation requirement when many multi-quasiparticle configurations are included in the basis, a numerical advancement based on the Pfaffian formula is introduced. With this new many-body technique, it becomes feasible to perform state-by-state calculations for the GT nuclear matrix elements of $\beta$-decay and electron-capture processes, including those at high excitation energies in heavy nuclei which are usually deformed. The first results, ${\beta }^{-}$ decays of the well-deformed $A=153$ neutron-rich nuclei, are shown as the example. The known $log\left(ft\right)$ data corresponding to the $B({\mathrm{GT}}^{-}$) decay rates of the ground state of ${}^{153}\mathrm{Nd}$ to the low-lying states of ${}^{153}\mathrm{Pm}$ are well described. It is further shown that the $B$(GT) distributions can have a strong dependence on the detailed microscopic structure of relevant states of both the parent and daughter nuclei.